<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
<canvas id="canvas" style="background-color: #000000;">您当前的版本不支持，请升级版本！</canvas>
<script type="text/javascript">
    //拿到画板
    var canvas = document.getElementById('canvas');
    canvas.width = 1000;
    canvas.height = 700;

    //获取绘图的上下文
    var context = canvas.getContext('2d');
    context.lineWidth = 10;
    context.strokeStyle = 'green';

    //绘制弧线
    context.beginPath();
    context.arc(200,200,100,0,Math.PI*2*0.75);
//    context.closePath();
    context.stroke();

</script>
</body>
</html>